The invention relates to a drive system for conveying rollers in a roller conveyor.
Roller conveyors, which are used to convey a wide variety of objects, generally comprise two mutually parallel supporting sections that extend in the longitudinal direction of the roller conveyor and between which a multiplicity of conveying rollers is arranged in series. These conveying rollers can be supported in such a way as to rotate freely, i.e. can be undriven, with the result that the objects to be conveyed move on the roller conveyor only by virtue of an acceleration previously imparted to them or, if the roller conveyor slopes, by virtue of their weight. However, roller conveyors of this kind also involve the use of driven conveying rollers to which rotation is imparted externally in order to move an object on the roller conveyor. In this case, all the conveying rollers of a roller conveyor or only certain conveying rollers at regular intervals may be driven, with freely rotatable conveying rollers being arranged between these driven conveying rollers.
The conveying rollers generally have a socket in their two longitudinal ends or end faces for an axle or shaft, by means of which they are supported in the supporting sections of the roller conveyor. In the case of the driven conveying rollers, a drive shaft is mounted at at least one end of the driven conveying roller, this drive shaft on the one hand being supported in the supporting section and on the other hand generally having, between the conveying roller and the supporting section, a driving wheel by means of which the conveying roller is driven. These driving wheels are generally chain wheels or gearwheels, which are driven by means of a chain or a toothed belt. In this case, a continuous drive chain or a continuous toothed belt generally extends over a multiplicity of driving wheels of a multiplicity of associated conveying rollers belonging to a conveying group, and these conveying rollers are thus driven jointly.
However, this arrangement has the disadvantage that the driving wheels and the toothed belt or drive chain are very close to the actual conveying roller, and there is therefore the risk of contact with objects to be conveyed. Another disadvantage is that the drive system, which is arranged between the conveying rollers and the supporting section, quickly gets dirty, which impairs its operation and increases wear. This drive system furthermore provides poor accessibility, especially when fitting or changing an endless drive belt or a drive chain, since all the rollers have to be removed to do this.
It is the object of the invention to provide an improved drive system for conveying rollers in a roller conveyor, in which the drive system is better protected from dirt and any possible contact with objects to be conveyed and provides improved accessibility.
The object is achieved by means of a drive system with the features given in claim 1. Advantageous embodiments will become apparent from the sub-claims.
In the drive system according to the invention, the drive arrangements, which drive at least some of the conveying rollers in rotation, are arranged completely within at least one supporting section or profile supporting the conveying rollers. In this way, a fully closed drive system is formed that offers better protection for the drive system from dirt. This closed configuration furthermore reduces the risk that objects to be conveyed or people standing close to the roller conveyor will come into contact with the drive system, thereby reducing the risk of damage to the drive system and to the objects to be transported or of injuries.
The drive arrangements advantageously comprise at least one driving wheel for each driven conveying roller, which is connected in a rotationally fixed manner by a shaft to the conveying roller, at least one group of driving wheels being driven by a common driving means. A drive system of this kind allows a simple and economical drive configuration since the conveying rollers can be driven by means of the driving wheels, via belts or chains that run through, for example.
The driving wheels are furthermore preferably designed as gear-wheels, which are driven by means of a common driving means in the form of a toothed belt or a chain. A toothed-belt drive or chain drive of this kind allows reliable power transmission to the individual conveying rollers. In addition, the toothed-belt drive, in particular, can be produced economically.
The shafts are expediently supported on both sides of the associated driving wheels in at least one supporting device arranged in the supporting section. In this way, reliable support for the driving wheels and the shafts that transmit the driving torque from the driving wheels to the conveying rollers is ensured. By virtue of the direct support close to the driving wheels, the transverse forces introduced into the shaft and bending moments associated with them are reduced, better and smoother running of the conveying rollers thereby being achieved overall.
One individual supporting device is preferably provided for a certain number of driven conveying rollers or for each individual driven conveying roller. This allows very flexible adaptation of the drive system to different numbers and arrangements of driven conveying rollers since the supporting devices can be mounted at those points in the supporting section at which driven conveying rollers are provided for the desired application.
The supporting device is preferably of essentially U-shaped design, the two free legs of the supporting device extending in parallel along the faces of the associated driving wheel and having the bearings for the shaft. As a result, the supporting device can be constructed in a very compact way, making it easy to arrange within a supporting section. The bearings can furthermore be arranged very close to the driving wheel, advantageous power transmission to the bearings combined with low bending moments on the shaft thereby being achieved. In this case, especially if the conveying rollers are intended only to carry light loads, the bearings are advantageously designed as simple sliding-contact bearings, in which the shaft for driving the conveying rollers is supported.
The supporting device is advantageously secured within the supporting section, preferably by being latched in. Corresponding grooves, in which the supporting device can be engaged by means of corresponding projections, can be provided for this purpose within the supporting section, which is preferably designed as an extruded aluminum section. This allows very rapid and economical assembly since no screwing operations or other time-consuming fastening operations involving additional fastening elements are required.
The supporting device can advantageously be divided in such a way that at least one of the free legs is removable. This configuration allows extremely easy fitting of the driving means, especially when this is an endless driving means such as a toothed belt. In this case, one of the free legs of the supporting device can be removed to allow the driving means to be fitted, the driving wheel and the shaft then continuing to be held by the second leg of the supporting device. The driving means, e.g. the toothed belt, can then be pushed easily onto the driving wheel, which is now accessible, and the leg removed can then be reattached to the supporting device, re-establishing support on both sides of the driving wheel.
The removable leg of the supporting device can preferably be connected to the remaining part of the supporting device and preferably also to the supporting section by being latched in. This further simplifies assembly since no involved assembly operations, such as screwing, are required. The parts of the supporting device are simply engaged or clipped into one another and likewise secured in the supporting section by being latched in. In this arrangement, the supporting section, which is preferably an extruded aluminum section, has corresponding latching means, e.g. corresponding latching grooves.
It is advantageous if the supporting device additionally forms a guide for the driving means. For this purpose, the U-shaped supporting device is dimensioned in such a way that it rests directly with its free legs against the faces of the driving wheel, the free legs thus simultaneously forming a lateral guide for a driving means passing through, e.g. a toothed belt. In addition, the distance between the circumferential surface of the driving wheel and that part of the supporting device that connects the two free legs to one another is expediently such that a guide is likewise provided in the radial direction and it is possible to prevent the driving means from slipping or jumping off the driving wheel in the radial direction.
The driving wheels and/or the supporting devices are advantageously manufactured from plastic. This allows extremely economical manufacture and offers a variety of design options to allow adaptation of the drive system to different applications. A certain elasticity in the supporting device can furthermore be ensured, thereby simplifying the process of engagement in the supporting section.
The supporting section is expediently of open construction on one longitudinal side, preferably on the longitudinal side facing away from the conveying rollers, to enable the drive arrangements to be inserted, this area of open construction preferably being closable by means of a cover strip. This allows easy access for installing and maintaining the drive system since all the elements of the drive system can be inserted laterally into the open supporting section. It is not necessary to remove the conveying rollers for this purpose since all installation, maintenance and replacement work on the drive arrangements can advantageously be carried out from the side facing away from the conveying rollers. After insertion, the area of open construction is then closed by means of the cover strip, which is preferably constructed from plastic, with the result that the entire drive system is fully encapsulated in the supporting section without the need for additional housing components to enclose the drive system securely. Moreover, this means that the drive system is reliably protected from dirt or damage and there is no danger that people will come into contact with the drive system, whereby it is possible to minimize the risk of injury.